Various types of cooking appliances are known in the patent literature. U.S. Pat. No. 4,073,970 describes a method of making an electric heating unit employing a sinuous strip of a gold/platinum alloy. U.S. Pat. No. 4,347,432 describes a glass ceramic cooking appliance employing a heating coil which heats the glass ceramic by radiation. U.S. Pat. No. 4,161,648 describes an electrical radiation heater for a glass ceramic plate which is spaced therefrom and heats the plate by radiation. U.S. Pat. No. 3,869,596 describes a cookware heater employing a printed circuit foil type heating circuit which is bonded to a ceramic or metallic surface.
There are known electric household appliances which provide warming of cooked food products and employ a foil heating element. An example is shown in the Sigg Catalog of 1987-1988 of sigg Ltd. of Frauenfeld/Switzerland.